Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cua triet, dua tren
soc van » hoc van, oc van, sac van
hieu va » lieu va, hieu qua
hieu vu » hieu ve, hieu su, dieu vu
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
cuu tre » cau tren, cau treo

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ty nang xa hoi. ((hieu vu) OR (hieu va)) cham soc van hanh vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang xa hoi. ((hieu vu) OR (hieu va)) cham soc van hanh vi ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang xa hoi. ((hieu vu) OR (hieu va)) cham soc van hanh vi ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang xa hoi. ((hieu vu) OR (hieu va)) cham soc van hanh vi ((cua tre) or (cuu tre))*.